1) Field of the Invention
The present invention relates to a unit which drives a light-emitting device as a light source such as a laser diode, wherein the device is used for an optical pick-up of an optical disk player.
2) Description of the Related Art
Fabrication of a light-emitting device applicable to an optical pick-up is usually separated from that of a driving unit used for driving the light-emitting device. Therefore, a procedure to electrically connect the light-emitting device with an output terminal of the driving unit is necessary in order to form a light-emitting apparatus.
When, for example, a laser diode is used as the light-emitting device, as shown in FIG. 1 of the attached drawings, a light-emitting device 2 that is sealed in a can package is connected with a unit 5 used for driving the light-emitting device via wiring lines 4 provided on a flexible printed wiring board 3, so that the device is flexibly positioned.
It is necessary to quickly power on and off the light-emitting device, i.e., the laser light source, because recording information at a high speed and at a high density is required for optical recording mediums such as a recordable optical disk and a rewritable optical disk in recent years.
However, because the wiring lines between the light-emitting device and the unit on the flexible printed wiring board behaves as a distributed-constant circuit in the light-emitting apparatus, ringing is caused by a high-speed switching over an electrical current. The ringing is a phenomenon that the electrical current supplied to the light-emitting device is unstable during the switching. As a result, a noise is generated in an optical pulse from the light-emitting device.